Cascaded Multilevel Voltage Source Inverter based active power filter for Harmonics and Reactive power compensation

This paper presents a cascaded multilevel Voltage Source Inverter (VSI) based shunt Active Power Filter (APF) for current harmonics and reactive power compensation due to nonlinear loads. The proposed approach comprises Low Pass Filter (LPF) in conjunction with Proportional Integral (PI) controller which is used to estimate the peak reference current and maintain the DCbus capacitor voltage of the cascaded inverter nearly constant. The cascaded multilevel active filter switching signals are derived from Triangularcarrier Current Controller (TCC), Periodical Sampling Current Controller (PSCC) and proposed Triangular Periodical Current Controller (TPCC). It gives better dynamic performance under transient and steady state operating conditions. The APF system is validated through extensive simulation under steady state and transient condition with different nonlinear loads. Comparative assessments of different current controllers are carried out. These simulation results reveal that the cascaded active filter effectively compensates the current harmonics and reactive volt amperes to improve the power quality.